We propose applying innovative measurement technology to develop and disseminate a comprehensive function and disability assessment instrument for use in gerontological research and practice. This technology offers an effective method to resolve the classic conflict between practicality and psychometric adequacy faced by traditional standardized outcome measurement technology. In this project we propose to develop, critically evaluate, and disseminate a Computer-Adapted Testing (CAT) instrument for the Late-Life Function and Disability Instrument (LATE-LIFE FDI-CAT), a promising outcome instrument designed to comprehensively assess and monitor changes in function and disability in older adults. To our knowledge this has never been done before in the field of gerontology and represents an innovative approach to improving outcome assessment for use with older persons. The principal aims of Phase I of this project are to: 1) Expand the original LATE-LIFE FDI item bank in the domains of Physical Function and Disability to incorporate additional functional and social role tasks appropriate for older adults;evaluate new items through expert feedback, cognitive testing and focus groups. 2) Develop final item calibrations for the revised Late-Life FDI item banks by collecting responses from a diverse sample of 500 older adults with functional limitations and disabilities. 3) Create a fully operational LATE-LIFE FDI-CAT system and demonstrate the accuracy, precision, and reductions in respondent burden of the LATE-LIFE FDI- CAT through real data simulation studies. And finally, 4) Evaluate the validity, reliability, and acceptance of the Late-Life FDI CAT in a sample of 100 older adults. The product of this Phase 2 STTR project will be a marketable CAT system for the assessment of function and disability for use in gerontological research and clinical practice. Adapted from the fixed-form, Late-Life FDI, this new function and disability outcome instrument will fill a critical void for a practical yet highly sensitive assessment instrument tailored for accurate and precise assessment of physical function and disability in older adults. PUBLIC HEALTH RELEVANCE: Outcome measures for older adults are becoming increasingly important and represent a major public health concern. This proposed project responds to the need for improved data collection, data analysis and data dissemination methods that can be used in clinical applications and public health research. The product of this STTR project will be a marketable CAT system for the assessment of function disability in older adults. Adapted from the fixed form Late-Life FDI, this new disability assessment will fill a critical void for a practical yet highly sensitive assessment system tailored for accurate and precise self-reported assessment of physical function and disability.